Deleting data from magnetic disk media and random-access memory may be accomplished by various methods, such as an erase operation where the memory data is overwritten with other data, a delete operation, or by removing power from the device. However, storing data indefinitely in magnetic disk media or random-access memory results in an aging effect which causes traces or remnants of data to remain even after a deletion or erasure operation has been performed on the memory or power to the memory is shut down.
This aging effect, known as data imprinting, defeats the ability to completely erase information stored in a memory. The data traces or remnants may provide sufficient information to determine what data was previously stored in the memory. The longer the information is stored in a memory cell, the greater the possibility that the data will be preserved by imprinting and subsequently detected even after erasure or deletion. Data imprinting could pose special data storage problems in security or similar private applications where the complete or guaranteed destruction of sensitive data may be highly desired.